Cavity resonator magnetron and strapping arrangement therefor



June.l5, 1948. J. 5. DONAL, JR, ETAL 2,443,445v

CAVITY RESONATOR MAGNETRON AND STRAPPING ARRANGEMENTS THEREFOR Filed March 29, 1944 2 Shets-Sheet '1 Patented June 15, 1948 CAVITY RESONATOR MAGNETRON AND STRAPPING ARRANGEIWENT THERE- FOR John S, Donal, In, Barremore B. Brown, and

Carmen Louis Cuccia, Princeton, N. J., assignors to Radio Corporation of America, a corporation of Delaware Application March 29, 1944, Serial No. 528,538

1 Claim. 1

Our invention relates to electron discharge devices useful at ultra high frequencies, more particularly to devices of the magnetron type employing cavity resonators.

Magnetrons utilized at ultra high frequencies and employing cavity resonators may be of several types. Those formed from a solid anode block have slats radially directed from the central cathode chamber, the slats providing the cavity resonators between adjacent anode segments. The slats may be enlarged at their inner ends to provide resonators having a circular transverse section. In another type a plurality of slats or fins are supported within a central space and extend radially toward and define a cathode space,

the inner edges of the slats serving as the anode segments and the slats and their supporting base providing cavity resonators between the anode resonators.

In magnetrons of this type, that is multi-segment type utilizing resonators, it is desirable to have the magnetron operate in only one mode, several modes being possible. In order to do this alternate segments are connected together or strapped together by means of conductors to insure operation in the desired mode. Magnetrons utilized at very high frequencies are of small size and it is diflicult to strap the anode segments together. Thus, accurate .and reproducible results in strapping are difiicult to accomplish, causing variations in dimensions in the spacing which not only affects the wavelength at which the magnetrons operate, but also the efi'iciency of operation.

It is an object of our invention to provide magnetrons having improved methods of strapping, promoting ease of construction, accuracy and reproducibility as to dimensions and spacings, thus insuring that magnetrons of the same size will operate at the same frequencies and at high efliciencie's.

The novel features which we believe to be characteristic of our invention are set forth with particularity in the appended claim, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawing in which Figure 1 is a top view with parts removed to show details of construction of an electron discharge device made according to. our invention, Figure 2 is a longitudinal section taken along the line II--II of Figure 1, Figure 3 is a longitudinal section taken along the line IIII[I of Figure 1, Figure 4 is an enlarged view of the anode segments and showing details of therstrapping members employed in the device shown in Figures 1, 2 and 3, Figure 5 is a perspective showing details of construction of a strapping member made accordingto our invention, Figure-6 is a section taken along the line VI--VI of Figure 4, Figure 7 is a sectional view of a modification of the construction shown in Figure 6, Figures 8 to 13, inclusive, illustrate the steps in the construction of another form of strapping arrangement according to our invention, Figures 14 and 15 show details of construction of an element utilized in Figures 8 to 13, inclusive, Figure 16 is a partial top View of a modification of the strapping arrangement shown in Figure 4, Figure 1'? is a section taken along the line XVIIXVII of Figure 16, Figure 18 is a partial section showing a modification of the construction shown in Figure 17, Figure 19 is a further modification of a strapping arrange ment shown in Figure 16, and Figure 20 is a section taken along the line IQ XX of Figure 19.

Referring to Figure 1, an electron discharge .device employing our invention is of the magnetron type and comprises an anode block 2! supporting a plurality of radially directed slats or fins 22 which extend toward and the inner ends of which provide the anode segments and define the cathode space in which the cathode 23 is axially positioned, this cathode being supported by the magnetic insert member 24 having oppositely disposed thereto a second magnetic insert member 25 which forms part of the magnetic circuit completed by a magnet having poles 24' and 25'. The cathode and inserts are supported by means of conducting bridging members 26 and 21 which are in turn insulatingly supported from the anode block by means of the bolts 28 and 29 insulated by means of insulating tubular members 30, 3|, 32 and 33, these bolts also being insulated from the block by means of the inserts 3t and 32'.

This electrode assembly is mounted on header member 35 to which is sealed an envelope 36, the header and envelope being made of non-magnetic material, for example, stainless steel. The oath ode and heater leads 3'! and 38 extend through the header and are sealed therein by means of the elongated insulating cup-shaped members 37' and 38'. One of the cavity resonators formed between the slats 22 has coupled thereto coupling member 39 which forms the inner conductor of coaxial line, the outer tubular conductor 40 of which has hermetically sealed thereto member 4 I, the inner member 39 also serving as a radiator which can be coupled into a waveguide. Cooling fins 42 may be secured to the header.

In accordance with our invention and as shown in Figures 4 and 6, each of the radially directed slats or anode elements 22 is provided with a slot 45 for receiving a strapping ring made according to our invention and shown in greater detail in Figure 5. This strapping ring 43 is provided with a plurality of deformations or extensions 48 normal to the plane: of the; ring and are positioned so that they contact alternate slats as shownin Figure 3. Two such rings are provided, one of which, ll, is of smaller diameter than the outer ring 45 and also being provided with. extensions 48' normal to the plane of the: strapping ring; these deformations engaging and being electrically connected to the other group of alternate anode slats. Thus during operation the voltage on adjacent anode segments are in phase opposition. As shown in Figure 6, the ring 4'6 is connected to the slat which is spaced from the ring 41 and likewise the ring 41 iselectrically connected at 48 to one of the slats while the, other ring 46 is positioned in space with respect thereto.

In the arrangement. shown in Figure '7 the slot 49 in the slats is. stepped so. that the rings are positively positioned with respect to each other, the smaller strapping ring engaging the inner step. and the outer ring engaging; the outer step, lateral. movement between the rings thereby be ingpreventedl.

In the case oimagnetrons formed: from a block by means. of slots" extending radially from a central chamber, a different approach to the problem is provided. Referring to. Figures 8 to 135, the slots i result in the provision of a plurality of anode segments 50., the inner ends of' which surround the cathode space. in which is axially mounted the. cathode 52. In the first step in providing. thcstrapping arrangement, the anode segments are recessed as indicated at 53. The element, shown in Figure 14 is then positioned as indicated in Figure This element; or spider 54 is provided with three projections 55, the outerportions of which are formed to. provide step 55. Likewise a. ring 51" provided; with a. step 58' is positioned Within the recess 53: in contact with the vertical. wall of the recess. After being secured in position the spider 54' and the ring 57 are out along the slots and alternate portions of" the ring; 51 are left as indicated inFigure 1.0-. To provide alternate. stepped portions at the inner ends of,1the, anode segments 50. the. spider isalso slotted so tha the step. portions: are left on different alternate. less. It is noted that the step portions. are mounted at the ends of thesegments in, between those. segments in which the step ring; p rtions. 511] are leit. The portions ofspider 54 in between the extensions 55 provide thev inner wall 54. as. shown in Figures 11 and 12. possible to position two rings 59" and 50' within the recess 53.. the outer ring being. supported. by' the step ring 5'! connecting alternate anode segments and the inner ring being supported by the step portions 56 of the spider, the relationship ofthe inner and. outer rings. being shown in Figure 13. Thus a, most accurate positioning ofthe rings results.

Another way of providing the step portion 51 is to. utilize the laminated construction shown in Figure, 20, the first and second laminations adjacent. the recess being extended one beyond the other t0.v provide a step on. which to place the outer rin Astill further method would be to use a ring having a step portion with intermediate portions, of less width and. then cutting; along the slots in the same manner as is done with the central spider.

Astill' further method would be to place sectors 51 of conducting material, such as shown in Figure. 7., on alternate segments adjacent the periphery of the recess;

A; further modification of the strapping ar- It is now rangement is shown in Figure 16. Here a pair of spiders are utilized, one of the spiders it being provided with extensions or legs 75 so that every 7 other anode segment between the slots TI is connected, by this spider. The second spider i2 is positioned over the first spider and the legs 13 engage the anode; segments in between the first mentioned group of segments. The relationship of. the two-spiders is shown in Figure 1'7, the ring portions of? the spider extending within the slots Til in the anode segments 1 ii.

In the modification shown in Figure 18 the outer spider 153" may have its inner portion deformed. as. indicated so that it passes under the ring portion of the top spider It.

In Figures 19 and 20 a still further form of strapping arrangement is disclosed. The anode block maybe made of a plurality of sheet ele men-ts as shown in Figure 20. Some of the sheet elements may be formed to provide recesses for receiving the legs $2 of the strapping member 8i which is in the form of a spider and thelegs 83' of the spider M, other sheets being formed to provide a space for the ring part of the spiders as shown at 85-. Figure 19 shows the anode block with the topplate of Figure 20 removed.

While we have indicated the preferred em- .bodiments of our invention of which We are now aware and have also indicated only one specific application for which our invention may beemplayed, it will be apparent that our invention is' by no means limited to theexact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the purpose for which it is employed withoutdeparting from the scope of our invention as set forth in the appended claim.

What we claim as new is:

An electron discharge device having a plurality of anode segments extending radially from acentral space defined by said segments, a cathode adjacent said anode segments for supplying electrons within said central space, said segments comprising slat-like elements, said slat-like elements having slots in. one end thereof, and. concentric ring-shaped strapping elements having JOHN S. DONAL, JR.

BARREL ORE B. BROWN".

CARMEN LOUIS CUCCIA.

REFERENCES CITED The following reterencesare of record. in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,063,342 Samuel Dec. 8, 1936: 2,111,263 Fritz Mar. 15, 1938' 2,242,888 Hdllmann May 20, 1941 2,408,234 Spencer Sept. 24, 1946' 2,408,235 Spencer Sept. 24-, 1946' 2;408,9.035 B iggs: et a1. Oct. 8, I946 FOREIGN PATENTS Number Country Date 445,084 Great Britain Apr. 2, 1936 Disclaimer .--John S. Donal, J12, Barremore B. Brown, and Carmen Louis Ouccia, Princeton, N. J. CAVITY RESONATOR MAGNETRON AND STRAPPING AR- RANGEMENT THEREFOR. Patent dated June 15, 1948. Disclaimer filed June 20, 1950, by the assignee, Radio Corporation of America. Hereby enters this disclaimer to the single claim of said patent.

[Ofiicial Gazette July 25, 1.950] 

